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Title: Effect of Acid on Surface Hydroxyl Groups on Kaolinite and Montmorillonite

Abstract

Mineral dust aerosol participates in heterogeneous chemistry in the atmosphere. In particular, the hydroxyl groups on the surface of aluminosilicate clay minerals are important for heterogeneous atmospheric processes. These functional groups may be altered by acidic processing during atmospheric transport. In this study, we exposed kaolinite (KGa-1b) and montmorillonite (STx-1b) to aqueous sulfuric acid and then rinsed the soluble reactants and products off in order to explore changes to functional groups on the mineral surface. To quantify the changes due to acid treatment of edge hydroxyl groups, we use 19F magic angle spinning nuclear magnetic resonance spectroscopy and a probe molecule, 3,3,3-trifluoropropyldimethylchlorosilane. We find that the edge hydroxyl groups (OH) increase in both number and density with acid treatment. Chemical reactions in the atmosphere may be impacted by the increase in OH at the mineral edge.

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1455297
Report Number(s):
PNNL-SA-117605
Journal ID: ISSN 0942-9352; KP1704020
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Zeitschrift fuer Physikalische Chemie; Journal Volume: 232; Journal Issue: 3
Country of Publication:
United States
Language:
English

Citation Formats

Sihvonen, Sarah K., Murphy, Kelly A., Washton, Nancy M., Altaf, Muhammad Bilal, Mueller, Karl T., and Freedman, Miriam Arak. Effect of Acid on Surface Hydroxyl Groups on Kaolinite and Montmorillonite. United States: N. p., 2018. Web. doi:10.1515/zpch-2016-0958.
Sihvonen, Sarah K., Murphy, Kelly A., Washton, Nancy M., Altaf, Muhammad Bilal, Mueller, Karl T., & Freedman, Miriam Arak. Effect of Acid on Surface Hydroxyl Groups on Kaolinite and Montmorillonite. United States. doi:10.1515/zpch-2016-0958.
Sihvonen, Sarah K., Murphy, Kelly A., Washton, Nancy M., Altaf, Muhammad Bilal, Mueller, Karl T., and Freedman, Miriam Arak. Wed . "Effect of Acid on Surface Hydroxyl Groups on Kaolinite and Montmorillonite". United States. doi:10.1515/zpch-2016-0958.
@article{osti_1455297,
title = {Effect of Acid on Surface Hydroxyl Groups on Kaolinite and Montmorillonite},
author = {Sihvonen, Sarah K. and Murphy, Kelly A. and Washton, Nancy M. and Altaf, Muhammad Bilal and Mueller, Karl T. and Freedman, Miriam Arak},
abstractNote = {Mineral dust aerosol participates in heterogeneous chemistry in the atmosphere. In particular, the hydroxyl groups on the surface of aluminosilicate clay minerals are important for heterogeneous atmospheric processes. These functional groups may be altered by acidic processing during atmospheric transport. In this study, we exposed kaolinite (KGa-1b) and montmorillonite (STx-1b) to aqueous sulfuric acid and then rinsed the soluble reactants and products off in order to explore changes to functional groups on the mineral surface. To quantify the changes due to acid treatment of edge hydroxyl groups, we use19F magic angle spinning nuclear magnetic resonance spectroscopy and a probe molecule, 3,3,3-trifluoropropyldimethylchlorosilane. We find that the edge hydroxyl groups (OH) increase in both number and density with acid treatment. Chemical reactions in the atmosphere may be impacted by the increase in OH at the mineral edge.},
doi = {10.1515/zpch-2016-0958},
journal = {Zeitschrift fuer Physikalische Chemie},
number = 3,
volume = 232,
place = {United States},
year = {Wed Mar 28 00:00:00 EDT 2018},
month = {Wed Mar 28 00:00:00 EDT 2018}
}